745781 has 4 divisors (see below), whose sum is σ = 748332. Its totient is φ = 743232.

The previous prime is 745757. The next prime is 745817. The reversal of 745781 is 187547.

745781 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 538756 + 207025 = 734^2 + 455^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-745781 is a prime.

It is a super-2 number, since 2×745781² = 1112378599922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (745711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 770 + ... + 1443.

It is an arithmetic number, because the mean of its divisors is an integer number (187083).

2⁷⁴⁵⁷⁸¹ is an apocalyptic number.

It is an amenable number.

745781 is a deficient number, since it is larger than the sum of its proper divisors (2551).

745781 is a wasteful number, since it uses less digits than its factorization.

745781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2550.

The product of its digits is 7840, while the sum is 32.

The square root of 745781 is about 863.5861277255. The cubic root of 745781 is about 90.6853440352.

The spelling of 745781 in words is "seven hundred forty-five thousand, seven hundred eighty-one".